Cooling unit for refrigerating apparatus



June 20, 1933. I H. A. GREENWALD 1,914,994

COOLING UNIT FOR REFRIGERATING APPARATUS Filed March 11, 1929 INVENTOR Patented June 20, 1933 UNITED STATES.

PATENT OFFICE HAROLD A. GBEENWALD, OI DETROIT; MICHIGAN; ASSIGNOR, BY MESNE ASSIGNMENTS.

. '10 KELVINATOB CORPORATION, OF DETROIT, MICHIGAN, A CORPOBATIONOF MICHI- GAN coonmc um non nnrmenna'rme arrmrus Application med 1mm 11,1929. Serial No. 346,205. i

Ordinarily a certain amount of oil used as lubricating means for the compressor of a refrigerating apparatus finds its way around the piston or istons of the compressor and into the re rigerating conduits of the apparatus. In the past such escaping oil has been carried along with the refrigerant into the flooded type cooling units and when the refrigerant, such as methyl chlo ride, is soluble with the oil, such oil was trapped in the cooling unit as the refrigerant of the mixture therein evaporated Consequently the oil did not return to the compressor to lubricate the same and such accumulation of oil in the cooling unit depleted materially the lubricating means for the compressor and prevented such compressor from getting the pro er lubrication.

. When a refrigerant such as $0 that is not soluble with oil is used, the oil floats on to of the refrigerant and may be carried 0 satisfactorily and returned to the compressor, however in the past, so far as 1 am aware, no satisfactory means has been devised for returning to the compressor oil that has commingled with a refrigerant such as methyl chloride that is soluble with the oil.

unit and return it to the compressor.

Therefore, it is an object of the present invention to rovidemeans, preferably asso cieted with t e cooling unit, for returning to the compressor the lubricating oil that It is also an object of the present invention to utilize a portion of the return conduit as a vaporizing chamber to permit the li uid refrigerant of the mixture rich with oi to evaporate in the cooling unit before passing therefrom to the compressor, and thereby aid the unit in its cooling and refrigerating work.

In the accompanying drawing Figure 1 is a diagrammatic view of a portion of a refrigerating apparatus and showing a cooling unit and associated means embodying my invention and I Figure 2 is a view of a slight modification. Referring now to the drawing,--1 is a cooling unit adapted to receive liquid refrig erant such as methyl chloride from a suitable container (not shown) and adapted to be mounted in a suitable freezing chamber of a refrigerator cabinet and the like Usu= ally the supply of refrigerant from the container to the unit such as 1 is regulated by a float chamber or capillary tube and in the present instance 2 may be either a float chamber or capillary tube and'is connected by a suitable conduit 3 to and adapted to regulate the supply of the refrigerant to the cooling unit 1. 4 designates the usual level of the refrigerant in the unit, 5 is the return line or conduit for returning to the compressor (not shown) the refrigerant gases developed by evaporation of liquid refrigerant in the unit 1 and having a coil 6 in the unit above the liquid level 4: terminating in a depending flared portion 7, and 8 is a substantially vertical tube having a restrictedpassage and suitably supported from and in substantially parallel relation to an upright side wall of the unit 1, preferably with the lower end 9 thereof spaced above the bottom wall 10 of the unit and with the u per end 11 thereof in the flared portion 7 oi the return conduit 5. Thus the construction and arrangement of the flared portion 7 and tube 8 is such that a Venturi or ejector type suction device is provided for withdrawing the contents of the tube 8 into the return conduit 5.

In use since a refri erant such as methyl chloride soluble with oil is used as the refrigerant, andsince oil used for lubricating the eva oration are received in the flared portion 7 o the conduit 5, and the velocity of such gases passing through this flared portion is mixture of lubricatin utilized to withdraw a mixture richer with oil from the unit at the bottom thereof through the tube 8 into the conduit 5 so that oil escaped from the compressor and finding its way into the refrigerant lines such as 3 will be returned to the compressor, and the said com ressor will be properly lubricated. In fact, e mixture drawn u wardlyin the tube 8 is decidedly richer wit oil than that discharged from the conduit 3 into the unit. In this connection the size of the passage in the tube 8 may be proportioned relative to the size of the passage in the conduit 3 so that the uantity of oil removed from the unit 1 will e substantially equal to that received by it. In any event oil is constantly withdrawn from the unit and is returned to the compressor so that it is properly lubricated.

The coil 6 provided in the unit 1 above the flared portion 7 is very important since it ermits the refrigerant of the mixture wit drawn from the tube 8 to evaporate in the unit 1 and thereby aid in the cooling and refri crating of the unit.

Iniigure 2 I have shown a slight modification in which the upper end 11 of the tube 8 is received in the throat 12 of a venturi 13 that may be connected at 14 by any suitable means to an end of the coil 6 or directly to a portion of the conduit 5 as ma be desired.

While it is believed that rom the foregoing description the nature and advantages -of the invention will be readil 'ap arent, I

desire to have it understood t at do not limit myself to what is herein shown and described and that such changes may be resorted to when desired as fall withinthe scope of what is claimed.

What I claim as my invention is: v

In a refrigerating apparatus, a tank constituting a cooling unit and containing a oil and refr" erant soluble with said oil, t e level of the mixture being such that s ace is provided in the tank at the top thereo for the evaporation of the refrigerant, a conduit having a coil substantially horizontally disposed within the tank and terminating above said liquid level in a depending flared portion that is adapted to receive the refrigerant gases resulting from evaporation, and a substantiall vertical tube partly submerged in the liquid mixture in substantially vertical alignment with said depending portion, having its lower end spaced slightly. above the bottom of the tank and having its upper end above the level of m si ature. HAROLD A. GREEMED. 

